1. Field of the Invention
This invention relates to a heat resistant material. Particularly the heat resistant material according to the invention is useful as kiln furniture in firing kilns and the like.
2. Prior Art
Kiln furniture as presently used in firing kilns for firing porcelain and similar goods, for instance, generally consists of refractory plates or slabs, e.g. 25-35 millimeters thick silicon carbide slabs. The slabs which support the goods to be fired are placed one above the other on tunnel kiln cars and are held mutually spaced by means of tubes or so-called "elephant feet". More often than never the refractory slabs have a weight of more than 50 kilograms, and thus they are very cumbersome to handle. The weight ratio of the kiln furniture to the goods to be fired sometimes reaches the order of 2:1. Of course, this means a tremendous energy waste. Another drawback inherent with the silicon carbide kiln furniture as used hitherto is that the strength thereof as time passes by is decreased due to oxidation. Still another drawback, in connection with the firing of porcelain, is that the porcelain goods may tend to stick to the carbide, unless the upper surface of the refractory plate is provided with a surface coating, such as an aluminum paint.
In an attempt to remedy the just mentioned drawbacks it has been proposed to use a special recrystallized, high purity silicon carbide (99% purity) composition. Also, it has been proposed to use an alumina - silicon carbide composition. In both cases, however, the material is a firebrick-like one which has a comparatively low bending strength and which, hence, must be comparatively thick to ensure the required supporting power. Further, with the known refractory slabs, problems have been encountered in avoiding sagging and/or warping of the slabs.